I think the idea was that 50 Hz was as low as you could go and not notice the lights blinking (and still keep it a nice round number). I'm not sure how 60 Hz was decided on, other than it fits well with the whole 360 degrees in a circle thing that all rotational devices do (motors/generators).

Post-war Japan was rebuilt by a combined effort by Europeans and Americans, so guess what? Northeastern Japan runs a 50 Hz and the southwest runs at 60 Hz. That's gotta make you go crazy if you travel, but I'm sure they've got that all figured out by now.

I'm in between bands at the moment, but am auditioning tonight with a prog-ish type band where the guitar player teaches guitar all day. The bass player is also a badass drummer who recorded (played) all the drum parts on the demo I just learned with all its freakishly weird time signature changes. I don't know what he or the singer do for income yet - and may never find out if I don't get the gig!